Which is better “Pyro Redevelopment” or “Copper Intensification”? Or, is that even a fair question? For me, both have their advantages and disadvantages. It’s not really a question of whether one is better than the other, it’s a question of what you prefer and how you want to achieve adding density to your wet/dry collodion negatives.
“Pyro Redeveloper”
The “Pyro Redeveloper” is made up of pyrogallic acid, citric acid, and distilled water. Along with that, you add a few drops of silver nitrate. I’ve used from 9% to 20% - it all works well. The idea behind this method is control. For example, for a Whole Plate negative, I’ll start with 60 ml of pyro, citric acid, and DH2O. I’ll add 10 - 20 drops of AgNO3. I’ll start by covering the plate in a weak solution of iodine. This “re-halgonates” the plate or makes it slightly sensitive to light again (think silver iodide). I’ll rinse it in distilled water and expose it to UV light for a minute or so. Next, in low light (no UV light), I’ll pour the 60 ml mixture on and off the plate (back into the beaker). I’ll do this until the solution has turned red - pulling the iodine from the silver. If I’ve gained the density I want, I’ll simply rinse the plate in distilled water and it will be finished. If I want more density, I’ll fill the beaker up again and repeat the process. You have a lot of control over this. It may take five minutes or 30 minutes, depending on how you mix your chemistry and the density you’re trying to achieve. The disadvantage may be handling the pyrogallic acid. And time, you may find this takes too long. The biggest advantage is control. You can achieve exactly what you want for density.
“Copper Intensification”
The “Copper Intensification” process is made up of a bleaching agent and a silver bath. The bleaching agent contains copper sulfate and potassium bromide. You bleach the silver on the negative to a “white” and then you drop it in a 12% - 20% silver nitrate bath. The intensification is immediate and can create super-dense negatives. You can adjust this process and do a mild intensification or really go for it and make a bulletproof (Dmax 5.0) negative. Either way, you don’t have a lot of control, but the process works very well. The cost can be prohibitive; a 12% silver bath can be $125 USD+. The bleaching compounds are not expensive. There are no real dangerous chemicals involved with this - the silver nitrate needs to be handled with care - but there’s nothing like the pyrogallic acid in the previous method.
Stay Tuned
I’m going to run some tests using both methods for my Platinum Palladium and Rawlins Oil prints. I’ll document Dmax and printing quality from each for each printing process. For years, I’ve used the pyro method. I used the copper method quite a bit many years ago. The cost of silver nitrate can be prohibitive, however, if you’re making enough negatives, know what printing works, and need the density for printing, it’s well worth it.
